My cousin has 2 children, the eldest is NT and the youngest SN. The youngest is a large child, though quite loving & gentle, could also be quite a handful when he got upset/angry.
They were lucky in that they had a good SN school a taxi ride away which he attended as a day pupil, but when he got to secondary age there wasn't anything locally - so he went to boarding school.
They thought it would be terrible and looked at moving, but taking into account the older child, their jobs, family, support systems etc it really didn't seem like a good idea.
The youngest (with SN) has dictated all of his life the kind of life they live, by necessity mostly, where they go, who they visit, the holidays they have, the friends that visit them, down to what they watch on TV - it's pretty much always been what DS2 needs - DS1 spends quite a lot of time with his Dad at football etc, so isn't excluded or ignored, but it's a different life to his mates.
DS2 goes to the boarding school, comes home every second weekend and it is working out brilliantly for all of them. My cousin, his wife and DC1 are enjoying having a different kind of home life - more relaxed, more freedom to go out etc (it's a shame DC1 is now an older teen with a girlfriend so he isn't benefitting from the changes as much as he would have if it had been this way a few years earlier, but even so it is helping them create a different relationship before he leaves home) and importantly DC2 LOVES his new school, he LOVES boarding and he LOVES coming home every other weekend - it's a WIN WIN WIN WIN situation.